I have a 2005 falcon xt fairmont C6 and was wondering how to get a little more power out of it so here are the things I was thinking about doing but don't know if they would benefit the car much

The car already has stiffer lower Springs and shock for better handling (did it more for looks to be honest )

Would I see a power increase from a 2.5 or 3 inch exhaust system and what kinda increase would I be looking at

Do these cars benefit from a cold air intake and what kinda increase would I be looking at

And I Heard u can reprogram the stock ecu or flash it to get more power ?? If so how much would the power increase be ..
Or is all of this just a waste of time

The cheapest mods are CAI, 200 cfi cat & a 2.5" exhaust. With a flash tune, you're looking at about 170-180rwkw. Going to a 3" exhaust won't do much on a stock engine unless you're planning to add boost later on.